The present invention relates to a process cartridge, and an electrophotographlc image forming apparatus in which a process cartridge is removably installable, and which form an image on recording medium.
Here, an electrophotographic image forming apparatus is an apparatus that forms an image on a recording medium with the use of an electrophotographic image forming method. As an example of an electrophotographic image forming apparatus, an electrophotographic copying machine, an electrophotographic printer (for example, laser beam printer, LED printer, and the like), a facsimile apparatus, a word processor, and the like can be included.
A process cartridge is cartridge that is removably installable in the main assembly of an image forming apparatus, and in which a single or plural processing means and an electrophotographic photosensitive drum, are integrally placed. More specifically, a process cartridge is: a process cartridge that removably installable in the main assembly of an image forming apparatus, and in which a charging means, either a developing means or a cleaning means, and an electrophotographic photosensitive member, are integrally placed; a cartridge that is removably installable in the main assembly of an image forming apparatus, and in which at least one of the processing means among a charging means, a developing means, and a cleaning means, and an electrophotographic photosensitive drum, are integrally placed; or a cartridge that is removably installable in the main assembly of an image forming apparatus, and in which at least a developing means among the aforementioned processing means, and an electrophotographic photosensitive member, are integrally placed.
Conventionally, an electrophotographic image forming apparatus that employs an electrophotographic-image-forming process employs a process-cartridge system, according to which an electrophotographic photosensitive member, and a single or a plurality of the aforementioned processing means, which act upon an electrophotographic photosensitive member, are integrally placed in a cartridge removably installable in the main assembly of an image forming apparatus. According to this process-cartridge system, an image forming apparatus can be maintained by the users themselves, without relying on service personnel, remarkably improving operational efficiency. Thus, a process-cartridge system is widely used in the field of an image forming apparatus.
Referring to FIGS. 16 and 17, the conventional technologies regarding the aforementioned process cartridge will be described.
A conventional process cartridge 200 comprises a cleaning unit 201, a development unit 202, and a developer containing unit 203. The cleaning unit 201 holds a photosensitive drum 204, a charge roller 205, a cleaning blade 206, a removed developer conveying member 207, and the like. The development unit 203 and developer containing unit 203 are fixed to each other, and jointly hold a development roller 209, a development blade 210, a developer conveying member 211, a stirring member 212, and the like.
The photosensitive drum 204 is rotated by the driving force transmitted thereto from a drum driving force inputting portion, which is provided on the main assembly side of an image forming apparatus, to a driving gear 213 positioned in such a manner that the axial line of the driving gear 213 aligns with the axial line of the photosensitive drum 4. On the other hand, the development roller 209 rotates as it receives the driving force from a driving gear 213, which receives the driving force from a driving gear 214. Further, a driving force is transmitted to the stirring member 212 in the developer containing unit 203, by the developer stirring member driving gear 216 that receives a driving force from the driving gear 214 by way of idler gears 215a and 215b. The developer conveying member 211 in the development unit 202 rotates as the driving force is transmitted thereto by a developer conveying member driving gear 218 to which driving force is transmitted from the developer stirring member driving gear 216 by way of an idler gear 217. The removed developer conveying member 207 rotates in the counterclockwise direction as the driving force is put into a removed developer conveying member driving gear 220 by way of an idler gear 219.
There has been a tendency to increase the developer capacity of a process cartridge in order to increases the cartridge-exchange interval, that is, the service life, of a conventional process cartridge such as the one described. As a result, the amount of the removed toner has increased, making it necessary to increase the capacity of the removed developer storing portion of a process cartridge.
With the increase in the amount of the removed developer, the load applied to the removed developer conveying member is bound to increase. On the other hand, in order to reduce the overall size of an image forming apparatus, the process cartridge size must be reduced.
The primary object of the present invention is to provide a process cartridge capable of efficiently storing the removed developer in its removed developer storage portion, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable.
Another object of the present invention is to provide a compact process cartridge, the size of which is realized by efficiently storing the removed developer in its removed developer storage portion, in spite of the increase in the amount of the removed developer, resulting from an increase in the service life of a process cartridge, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable.
Another object of the present invention is to provide a process cartridge in which the increase in the amount of the load placed upon a removed developer conveying member for conveying the removed developer, does not affect the rotation of the photosensitive drum, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable.
Another object of the present invention is to provide a process cartridge which is removably installable in the main assembly of an electrophotographic image forming apparatus, and which comprises: a first frame portion; a second frame portion pivotally attached to the first frame portion; an electrophotographic photosensitive drum, which is placed in the first frame portion; a developing member, which is placed in the second frame portion to develop an electrostatic latent image formed on the photosensitive drum, with the use of developer; a cleaning member, which is placed in the first frame portion to remove the developer remaining on the photosensitive drum; a removed developer conveying member, which is placed in the first frame portion to convey the developer removed by the cleaning member; a drum driving force transmitting member, which is placed in the first frame portion to receive the force for rotationally driving the photosensitive drum, from the main assembly of an image forming apparatus, when the process cartridge is in the apparatus main assembly; a developing member driving force transmitting member, which is placed in the second frame portion to receive the force for rotationally driving the developing member, from the apparatus main assembly, when the process cartridge is in the apparatus main assembly; and a driving force transmitting member, which is placed in the second frame portion to transmit to the removed developer conveying member, the force received by the developing member driving force transmitting member from the apparatus main assembly, in order to rotate the removed developer conveying member, and also to provide an electrophotographic image forming apparatus in which such a process cartridge is removably installable.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.